1. Field of the Invention
This invention relates to a slide fastener and more particularly to a pair of slide fastener stringers of substantially continuous or endless length.
2. Prior Art
It is the usual practice of slide fastener manufacturers to conjoin a multiplicity of predetermined individual unit lengths of fastener stringers to form extended, continuous lengths of such stringers which are conveniently referred to herein as "slide fastener chain" as contrasted individual slide fastener products, the resulting slide fastener chain being subsequently subjected to dying, parts assembling and other finishing operations.
One conventional way of conjoining or interconnecting discrete, adjoining lengths of stringers was to superpose their respective end portions one on the other and staple them together. Another alternative way known in the art was to lay adjoining stringers in the same plane with their respective ends held in confronting relation and sew or otherwise secure them together with use of an adhesive film. Such known conjoining procedures were disadvantageous in that the joints of unit stringers connected in a continuous row would often present an obstacle to the running of a slider along the stringers when tested for the opening and closing performance of the fastener chain. Therefore, it was necessary to discontinue the operation of the testing machine every so often in order to disconnect the joints of adjoining unit stringers to mount the slider. Further, the slide fastener chain to be used for fishing nets, which is manufactured by conjoining individual fastener lengths, has a further drawback in that the rows of fastener elements which have been coupled together on the respective stringer tapes are prone to become uncoupled or disengaged at and from where the joints are located when stresses are applied tending to split the stringers apart.